The role of IL-17 promotes spinal cord neuroinflammation via activation of the transcription factor STAT3 after spinal cord injury in the rat.

Study Design: In this study, we investigated the role of IL-17 via activation of STAT3 in the pathophysiology of SCI.

Objective: The purpose of the experiments is to study the expression of IL-17 and related cytokines via STAT3 signaling pathways, which is caused by the acute inflammatory response following SCI in different periods via establishing an acute SCI model in rat.

Methods: Basso, Beattie, and Bresnahan hind limb locomotor rating scale was used to assess the rat hind limb motor function. Immunohistochemistry was used to determine the expression levels of IL-17 and p-STAT3 in spinal cord tissues. Western blotting analysis was used to determine the protein expression of p-STAT3 in spinal cord tissue. RT-PCR was used to analyze the mRNA expression of IL-17 and IL-23p19 in the spleen tissue. ELISA was used to determine the peripheral blood serum levels of IL-6, IL-21, and IL-23.

Results: Compared to the sham-operated group, the expression levels of IL-17, p-STAT3, IL-6, IL-21, and IL-23 were significantly increased and peaked at 24 h after SCI. The increased levels of cytokines were correlated with the SCI disease stages.

Conclusion: IL-17 may play an important role in promoting spinal cord neuroinflammation after SCI via activation of STAT3.